Periodic Table |
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| What is the Periodic Table Showing? | Periodicity |
The INTERNET Database of Periodic Tables
There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).
| Year: 1900 | PT id = 1284, Type = formulation data element review structure |
History of the Discovery of the Group 18 (erstwhile Group 0) Elements
John Marks has provided a concise history of the discovery of the Group 18 elements and the element name"Nitron/Radon".
Radioactivity was discovered by Becquerel in 1896 and the Curies noted transferred radioactivity rather like the induction of electric or magnetic charge. Radon was discovered in 1900, by Dorn in Halle; Rutherford discovered thoron in 1899; and Debierne discovered actinon in 1903. The time-line is:
- 1868 Lockyer observed the spectrum of helium in the solar corona
- 1894 Ramsay discovers argon
- 1895 Ramsay isolates helium
- 1898 Ramsay discovers krypton, neon & xenon
- 1899 Curie observes an emanation from radium
- 1899 Rutherford observes an emanation from thorium
- 1900 Dorn identifies radon
- 1902 Rutherford & Soddy characterize thoron
- 1903 Rutherford & Soddy isolate radon
- 1903 Debierne observes an emanation from actinium
- 1904 Ramsay names the isotopic emanations exactinio, exradio & exthorio and surmises they are one element, probably an inert gas
- 1908 Professor Sydney Young’s "Stoichiometry" has a periodic table shows niton, Z = 86
- 1909 Ramsay characterizes niton as a group 0 inert gas
- 1910 Cameron's "Radiochemistry" describes the radioactive displacement law
- 1912 The name "niton" accepted by the International Commission for Atomic Weights
- 1913 Soddy expounds theory of isotopes
- 1913 Rydberg's periodic table has Nt (86) for the last inert gas
- 1919 Irving Langmuir's PT has Nt as the last inert gas
- 1922 Niels Bohr’s PT has Nt (86) as the last inert gas
- 1923 GN Lewis’s PT has Nt as the last inert gas
- 1924 CRC’s Handbook of Chemistry and Physics has niton as the last member of Group 0
So niton (from Latin nitens = shining) was noticed by the Curies in 1899 as an emanation from radium. That same year Rutherford noted an identical emanation from thorium, and in 1903 Debierne discovered the same emanation from actinium. All three ('radon', 'thoron' and 'actinon') were identified as an element by Ramsay in 1904 and characterized by him in 1909.
Ramsay named the element niton after its most prominent property viz. that it glowed in the dark.
With the introduction of Soddy's isotopes, it became clear that: thoron was Nt-220, radon was Nt-222 & actinon was Nt-219.
There are natural traces of other isotopes (e.g. Nt-217, Nt-218) from beta disintegration of astatine. So "radon" was just one isotope of niton.
The foregoing history of niton is uncontroversial and the name niton, Nt, for Z = 86 dates at least from Professor Young´s textbook of stoichiometry in 1908.
In 1912, the name 'niton' was adopted by the International Commission for Atomic weights. Rydberg's PT of 1913 has Nt as the last inert gas, as does Irving Langmuir's PT of 1919, Niels Bohr's PT of 1922, GN Lewis's PT of 1923 and even the CRC's Handbook of Chemistry and Physics in 1924.
John Marks concludes:
"Niton, Nt, for Z = 86, was thus established by its discoverers and accepted by the chemistry (and physics) establishment. Radon, Rn, is an error perpetuated by IUPAC [amongst its many sins].
"Radon is an isotope. We do not refer to hydrogen as 'protium', so why are we referring to niton as 'radon'?"
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| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
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